1. Field of the Invention
A venous blood collection assembly via vacuum tubes for conveniently minimizing accidental needlesticks in users and maximizing safety for patients.
2. Prior Art
Since the recognized advent of the acquired immunodeficiency syndrome (AIDS) in 1981 and recognition that other bloodborne viruses, such as hepatitis B virus (HBV) and hepatitis C virus (HCV), are being transmitted to healthcare workers (HCWs) at alarming rates via accidental needlestick exposures to blood or other body fluids, maximal efforts toward preventing such exposures have been stressed by the medical device industry, as well as the U.S. Government. Over a thousand patents have issued or pend for safer devices capable of shielding HCWs from an estimated 800,000 accidental needlesticks during the use of approximately six billion hollow steel needles used annually in US patient care. It is expected that within nine months after our President""s signature of the Needle Stick Safety Prevention Act on Oct. 6, 2000, the common use of safety engineered needlestick prevention devices will be mandatory throughout the USA.
In the field of assemblies patented and pending for blood collection via vacuum tubes, the following prior art seems cogent:
Needles originally designed for blood collection into vacuum tubes comprised a leading xc2x11.0xe2x80x320 to 23 G first needle sharp on the leading end and a second xc2x10.5xe2x80x320 G needle sharp on the trailing end permanently affixed into a single unit by a hub having a slip connector on the leading end for attachment of a protective scabbard for the first needle and a threaded connector on the trailing end for reversibly affixing the second needle into the cavity of a vacuum tube holder before insertion of the vacuum tube. Also, the trailing end of the hub was made with a slip connector for a protective scabbard for the second needle, such that the open ends of each scabbard abutted one to another and could be sealed further with a breakable label for the assembled sterilized contents in a very compact package. Later, was added an elastomeric tubular sleeve with a closed trailing end and an open leading end affixed by elastic recoil to the trailing end of the hub holding both needles. The purpose of this air-tight sleeve was to prevent blood leakage into the cavity of the holder before the vacuum tube is inserted, to minimize leakage between insertions of more than one vacuum tube, and to minimize leakage after the last vacuum tube has been extracted from the cavity of the vacuum tube holder. When it became obvious that neither the first, nor the second needle should be manually recapped with its originally supplied protective scabbard, the lids of containers for used sharps in blood collection stations and on portable blood collection trays were modified with special receptacles which allowed HCWs to safely detach the hub holding two exposed sharp needles by unscrewing the trailing end of the hub from the vacuum tube holder into the cavity of the sharps container, using one hand while doing so.
Following blood collection apart from handy sharps containers with appropriate needle removal receptacles, it became obvious that the exposed first needles are hazardous for patients, phlebotomists and other HCWs. The early remedies were vacuum tube holders with outer sleeves which slide forward and lock after use to protect finger access to the bevel of the first needle used to withdraw venous blood. Such devices proved cumbersome, required two hands to activate the protective sleeve after the leading needle is withdrawn from a patient""s vein and require disposal of the vacuum tube holder containing the first needle and the second needle which punctures the leading cap on vacuum tubes.
Commercial development then turned toward intrinsic means for shielding the bevel and shank of the first needle, especially by methods applicable to syringe/needle combinations used for giving injections. A variety of devices of two fundamental types evolved rapidly.
The first type basically comprises a variety of sleeves permanently attached to the leading part of the needle which can be finger-manipulated to safely cover the bevel and shank after the needle is withdrawn from the vein of a patient. One of the first was the ICU Medical Blood Collection Needle twice usual length, over which a sliding tube is manipulated to lock over and shield the leading bevel and shank after withdrawal from a vein, along with a trailing needle whose hub screws into the leading end of a standard vacuum tube holder. Although the vacuum tube holder could be used again with another similar needle, the length of the needle beyond the vacuum tube holder made venous access awkward for many phlebotomists, and provided no intrinsic means for safe disposal of the trailing second needle. To obviate such problems Sims-Portex developed the Needle-Pro(trademark). a singly hinged plastic shield permanently attached to the first needle hub which swings from one side to cover and lock in the exposed needle shank and bevel. Becton-Dickinson developed a doubly hinged device, called Safety-Glide(trademark), attached similarly which slides forward and locks to enclose and protect the first needle with straight forward finger action. Others developed compressed spring operated systems whose latches permitted the spring extension of protective caps over the first needle bevel after use. Still others, such as Retractible Technologies developed the Vanish Point(trademark) (U.S. Pat. No. 5,423,758) spring-operated device attached to the trailing end of the first needle hub which, with forward pressure exerted on an inserted sleeve by means of a trailing hinging cap on the vacuum tube holder, releases the spring such that the first and second needles vanish, along with their common hub, into the confines of the cavity in the holder whose trailing end is closed by the hinging cap.
The second type of intrinsic means for shielding the first needle is exemplified in the Bioplexus Puncture Guard(copyright) system which embodies an obturator with a blunt tip which is passed through the bore of the first needle to extend beyond the sharp tip of the needle bevel and locked in place by a latch mechanism inside the needle hub, when the user exerts increased forward pressure on a vacuum tube inserted into the vacuum tube holder, after final use for blood collection.
Currently in California, where the use of safety-engineered needles for preventing needlesticks is universally directed under CPL 2-2.44D (Nov. 5, 1999), the use of the Becton-Dickinson Safety Glide(trademark) or Bioplexus Puncture Guard(copyright) protectors for the first needles, in conjunction with modified reusable vacuum tube holders appears most common for blood collection. The embodied modifications in the vacuum tube holders consist of differing manually activated latch mechanisms for expanding the diameter of the leading aperture in the vacuum tube holder, such that the threaded trailing end of the first and second needle hub can be dropped through a large diameter aperture through the top of a sharps container when convenient, and the vacutainer holder can be reused subsequently.
The Becton-Dickinson Safety Glide(trademark) system retains at least three potential hazards: (a) the leading needle must be withdrawn from a patient""s vein before the needle can be protected; (b) the latch for releasing the trailing needle from the reusable vacutainer holder is not always easy to operate; and (c) the bulk and external leading diameter of the modified Vacutainer(trademark) holder provides a suboptimal angle of venous access by and venous withdrawal of the leading needle. The Bioplexus Puncture Guard(copyright) system retains at least three potential hazards: (a) advancement of the obturator through the leading needle bore before the needle is withdrawn could cause venous injury; (b) the latch in the reusable Drop It(copyright) vacuum tube holder for releasing the trailing needle sometimes fails, such the obturator and the leading needle bevel are further advanced into the vein of the patient with actual vein injury; and (c) poor alignment of the leading needle bevel in relation to the latch on the Drop It(copyright) may increase the angle of venous angle of access and withdrawal with the bevel of the needle always upward. Both systems present reusable vacuum tube holders whose use is limited to recommend numbers of uses and which are not easy to clean after use.
The instant invention differs from all the prior art in the following respects:
(a) The blood collection needle and the vacuum tube holder are fabricated in a single assembly wherein the first needle slidingly contained in a small diameter needle holder is linked by means of breakable female slip connection to a mating male slip connection on the leading end of a long rigid transparent tube permanently embodied into the leading end of a vacuum tube holder wherein the second needle is permanently housed such that the lumen of the first needle is confluent with that of the second until the mating slip connections are broken after use for collecting blood into one or more vacuum tubes. Because the second needle is permanently embodied and recessed in the leading cavity of the vacuum tube holder and the first needle hub becomes trapped inside the needle holder during withdrawal and twisting of the long rigid tube embodied on the leading end of the vacuum tube holder, the beveled tip and shank of neither needle is exposed to cause injury to a user, a patient or a bystander after use of the assembly which becomes safely disposable in two parts, neither of which can be reused; but are shielded immediately after use, such that immediate disposal into a sharps container is not critical.
(b) Embodiment of a slip connection between the first needle hub and a rigid tube for guiding the thrust and retraction of the first needle hub into a predetermined site of wedge impaction in the trailing conical bore of the first needle holder, as taught in Shields U.S. Pat. No. 5,007,901 (Apr. 16, 1991), U.S. Pat. No. 5,401,250 (Mar. 28, 1995), U.S. Pat. No. 6,126,621 (Oct. 03, 2000), is not taught or claimed in any of the cited prior art applicable to blood collection via vacuum tubes.
(c) Embodiment of a leading dorsal tether or head projection on the first needle holder, as taught in Shields U.S. Pat. No. 5,350,368 (Sep. 27, 1994), U.S. Pat. No. 5,401,250 (Mar. 28, 1995), U.S. Pat. No. 5,858,004 (Jan. 12, 1999) for holding pressure over a vein and stabilizing the leading end of the needle holder such that the needle can be withdrawn comfortably and safely from a vein without exposure of the bevel or shank during or after withdrawal, is not taught or claimed in any of the cited prior art applicable to blood collection via vacuum tubes.
(d) Embodiment of a syringe piston in the needle holder for stabilizing the thrust of the first needle and preventing blood leakage from the needle holder after the needle is retracted into the bore is not taught or claimed in any of the prior art cited.
(e) It would appear from the prior art cited that sleeves which slide over the first needle or over the vacuum tube holder and the Vanish Point(copyright) system resemble the instant invention most closely in purpose. However, none of the mechanical details patented in each are embodied in this innovative system.
The object of this invention is to provide a simple, efficient and cost-effective means to make blood collection into vacuum tubes as safe as possible for patients and HCWs. Outstanding advantages over the Prior ART might be listed as follows:
1. Being a completely integrated assembly, the user opens one sterile package and everything is ready for use, except for removal of the disposable scabbard initially supplied for shielding the first needle before venous insertion.
2. Lacking springs, latches and sliding parts necessitating use of both hands, the assembly should prove relatively free from mechanical and user failures.
3. Owing to a relatively small diameter of the leading end of the needle holder compared with that of the vacuum tube holder, a superior and low angle of needle approach to and withdrawal from a selected vein will be achieved for the benefit of the patient and for preventing venous injury, especially in small or hard-access-veins.
4. Owing to a leading means for stabilizing the leading end of the first needle holder while simultaneously holding finger pressure over the selected venipuncture site, the bevel and shank of the first needle will never be exposed during or after venous withdrawal. Equally important, with the needle already shielded, finger pressure with the non-dominant hand can be sustained as long as optimal for preventing vein injury and bleeding; while the dominant hand can be used for sundry purposes.
5. Owing the permanent embodiment of the second needle in the leading end of the vacutainer holder, the bevel and shank of this needle are permanently recessed, such that needlestick injury is impossible, except in instances wherein the internal diameter of the vacutainer is greater than that of the finger of a HCW who sticks a finger into the cavity for no purposeful reason or some child is given a used holder to play with. This problem is soluble by making vacuum tube holder internal diameters more fitting to the external diameters of currently inserted 7.0 mL or pediatric vacuum tubes, instead of expanding their cap diameters to fit holders for archaic 10 mL. vacuum tubes of similar length.
6. The current industry approach to (5) is that reuse of vacuum tube holders xc2x150 times saves patient and user costs appreciably and is convenient in blood collecting stations wherein space for disposal of used ones in sharps containers can be rapidly overloaded by their bulk, Those pursuing patient, as well as user safety, might rebut as follows:
The elastomeric cap covering the bevel and shank of the second needle embodied into, or temporarily inserted into a vacuum tube holder, was designed to stop leakage of venous blood under 5-20 cm. of hydrostatic venous pressure through the trailing end of the blood collection assembly until an inserted vacuum tube accelerates retrograde flow via the bore of the second needle. However, after the first puncture of the trailing end of the elastomeric cap occasioned by insertion of the first vacuum tube and others with or without diluents essential to the analysis of collected whole blood, the elastomeric cap will leak more and more venous blood under ambient venous pressure into the cavity of the vacuum tube holder, more or, less proportional the number of times the trailing end of the elastomeric cap covering the trailing end of the second needle has been punctured. The logic consequences are that all vacuum tube holders, used more than once for blood collection, are likely to have their bores and second needle attachments contaminated with blood leakage from patients sampled sequentially. Simple peroxide, hypochlorite, steam, alcohol, autoclave, gamma-radiation or fluorine sterilizatuon of the vacuum tube holder after each use being impractical, it would seem simpler not to reuse such vacuum tube holders more than once or, at least provide protocols whereby reusable vacuum tube holders can be sustained reasonably clean. Because unit cost and disposable bulk factors are cogent, a further object of this invention is to disclose efficient, cost-effective use of reusable, as well as single use vacuum tube holders.